Technical Field
The present invention relates to a substrate holding device that holds a substrate using an electrostatic chuck. In addition, it relates to a semiconductor fabrication device provided with said substrate holding device, and to a substrate clamping ascertainment method using said substrate holding device.
Background Art
In the past, electrostatic chucks have been used to fixedly hold substrates in transport mechanisms and semiconductor fabrication devices.
If a substrate is not completely secured to an electrostatic chuck, this may lead to problems, i.e. the substrate may fall off the electrostatic chuck, develop cracks during substrate transportation or substrate processing, etc. For this reason, it is believed that when a substrate is secured to an electrostatic chuck, it is important for the substrate to be reliably clamped.
In the prior art, ascertainment as to whether a substrate has been clamped to an electrostatic chuck in a normal manner was based on a technique that involved, as described in Patent Document 1, measuring capacitance between the substrate and an electrode that formed part of the electrostatic chuck, and ascertaining the clamped state of the substrate based on the amount of change in the capacitance.